Permafrost Terrain Stability and Thermokarst Monitoring: - Arctic LCC

113. Murton, J.B., 2013, Ground ice and cryostratigraphy in Shroder, J., and others, eds.,
Treatise on geomorphology: San Diego, Academic Press, v. 8, Glacial and Periglacial
Geomorphology, p. 173–201.
This book chapter provides a review on ground ice and cryostratigraphy–the stratigraphic
analysis of ice-rich permafrost. The description and genesis of ice in frozen ground are
reviewed and demonstrated through case studies related to 1) the transition zone at the top
of permafrost, (2) massive ice and icy sediments, (3) ice wedges, and (4) yedoma and
related deposits. A section is also included on mapping ground ice. Detailed information on
cryostructures in permafrost is given in table 1 of the chapter, and information on
cryofacies of frozen sediments is given in table 2. The chapter concludes with a
recommendation on future research needs in the field of crystratigraphy.
114. Nelson, F.E., Hinkel, K.M., Shiklomanov, N.I., Mueller, G.R., Miller, L.L., and
Walker, D.A., 1998, Active-layer thickness in north central Alaska—Systematic
sampling, scale, and spatial autocorrelation: Journal of Geophysical Research, v. 103,
no. D22, p. 28963–28973.
This paper measures active-layer depth at many sites with a wide range of terrain, soil, and
vegetation characteristics across the Arctic Coastal Plain and Arctic Foothills, Alaska.
Along 100-m grids at 7 sites, a graduated steel rod was placed in the soil to measure activelayer
depth. The authors evaluated their approach and found that the depth at probe
resistance corresponds closely to the frost table. They observed high spatial, but low
temporal heterogeneity in active-layer depth that varied between the coastal plain and the
foothills. Samples were taken during 2 years with similar air temperatures, which may
explain the low temporal variability in active-layer depth. Active-layer thickness was
influenced by microclimate, hydrology, soil moisture, and vegetation. This authors
attempted to use a network of monitoring sites that were established to collect a wide range
of ecological data across northern Alaska. The authors learned, however, that, although the
100-m scale was suitable for the coastal plain, narrow water tracks and tussock tundra in the
foothills led to variations in thaw depth over short lateral distances. Reconnaissance
sampling in this area was recommended to determine the appropriate sampling scale for
particular variables.
115. Nicol, S., Roach, J.K., and Griffith, B., Spatial heterogeneity in statistical power to
detect changes in lake area in Alaskan National Wildlife Refuges: Landscape Ecology,
p. 1–11.
This paper investigates how the statistical power to detect trends in lake sizes in the
National Wildlife Refuges of Alaska are affected by the area of analysis and the number of
years of monitoring. The authors used large study areas (930–4,560 km 2 ) and smaller cells
(2.6–25.9 km 2 ) during 4–50-year periods, and observed that trends could be detected within
5–15 years, that trends smaller than 2.0percent per year required more than 50 years to
detect, and that there was substantial spatial variation in the time required to detect changes
among the smaller cells. The authors suggested that even small trends may be ecologically
meaningful, and so long-term monitoring should be established as early as possible.
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